diff options
| author |   Peter Zijlstra <peterz@infradead.org> | 2025-10-27 12:01:33 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2025-10-28 15:00:48 +0100 |
| commit | af13e5e437dc2eb8a3291aad70fc80d9cc78bc73 (patch) | |
| tree | 1d744aa5b71354b60cc3bb5cb79f6f5142fb78bf /net/openvswitch/ssh:/git@git.zx2c4.com/git: | |
| parent | sched/topology,x86: Fix build warning (diff) | |
sched: Fix the do_set_cpus_allowed() locking fix
Commit abfc01077df6 ("sched: Fix do_set_cpus_allowed() locking")
overlooked that __balance_push_cpu_stop() calls select_fallback_rq()
with rq->lock held. This makes that set_cpus_allowed_force() will
recursively take rq->lock and the machine locks up.
Run select_fallback_rq() earlier, without holding rq->lock. This opens
up a race window where a task could get migrated out from under us, but
that is harmless, we want the task migrated.
select_fallback_rq() itself will not be subject to concurrency as it
will be fully serialized by p->pi_lock, so there is no chance of
set_cpus_allowed_force() getting called with different arguments and
selecting different fallback CPUs for one task.
Fixes: abfc01077df6 ("sched: Fix do_set_cpus_allowed() locking")
Reported-by: Jan Polensky <japo@linux.ibm.com>
Reported-by: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Jan Polensky <japo@linux.ibm.com>
Closes: https://lore.kernel.org/oe-lkp/202510271206.24495a68-lkp@intel.com
Link: https://patch.msgid.link/20251027110133.GI3245006@noisy.programming.kicks-ass.net
Diffstat (limited to 'net/openvswitch/ssh:/git@git.zx2c4.com/git:')
0 files changed, 0 insertions, 0 deletions